1. Field of the Invention
The present invention is relates to an improved buoyancy aid for floating legs and lower torso of a swimmer as during the development of arm stroking techniques, strength and endurance, especially to a buoyancy aid which has adjustable buoyancy and an improved contacting surface for reliable and convenient use.
2. Description of Related Art
Swimming is a popular exercise and excellent method for body figuration and health maintenance. However, to get the most effective result or body benefit after swimming, especially for a competitive swimmer, efficient swimming posture should be learned by swimmers first. Except for the help of a good trainer, various different forms of swimming practice aides and other devices are usually useful to assist swimmers with swimming learning. In particular, these aids or devices are also beneficial to swimmers practicing different ways of swimming, including the butterfly, backstroke, breaststroke and freestyle swimming stroke. One kind of the aids or devices is in regard to flotation devices which are employed to effect or supplement flotation and provide total or partial immobilization of a portion or portions of a swimmer""s body in order to concentrate on the development of techniques involving other body portions involved in a total stroke makeup. Examples of devices of this nature are buoyancy aids for legs and kickboards which have been developed in a variety of forms. In regard particularly to leg buoyancy aids, such devices are employed to provide flotation for the legs of a swimmer and to substantially immobilize the legs of a swimmer against movement relative to each other, while permitting the development of improved techniques or strength and endurance with respect to arm motions and/or breathing techniques.
Leg buoyancy aids of various types have been developed primarily from inflated or foam materials which within limited size constraints produce significant buoyant assist to the legs of a swimmer. xe2x80x9cKick Boardxe2x80x9d, for instance, is usually formed with a rectangular shape by using foam material. U.S. Pat. Nos. 4,406,628, 4,781,638 and 5,518,429 all disclose a specialized kind of kick boards. As how a kick board is named, kick boards are usually hand-held to train the legs of swimmers. In a circumstance without enough professional equipment, kick boards can be used as a leg buoyancy aid by holding one of the kick boards between legs of a swimmer. It is understood that the rectangular shape of a kick board is hard to hold by legs. Therefore, a buoyancy aid having two enlarged portions joined by a thinner connecting portion to position the enlarged portion above and below the legs of a swimmer is helpful to be conveniently held. In some instances, composite flotation elements have been provided which effect some extent of conformance with body contours to assist in the selective retention of the leg buoyancy aid with minimal leg effort on the part of the swimmer. Rademacher U.S. Pat. No. 4,379,704 shows a similar device following the same design idea. However, while the flotation objective has been generally achieved by most of these devices, the adaptability of these devices to swimmers of different sizes and weights has been inadequate in many instances. In addition, some of these devices have not been constructed in such a fashion and surface as to be easily or steadily held by a swimmer which inevitably results in the need of struggling from the swimmer to hold these buoyancy aids.
Accordingly, an object of the present invention is to provide a buoyancy aid which is effective in supplementing the buoyancy of legs of a swimmer for exercise or drills directed to improving breathing techniques or arm stroking techniques, strength and endurance.
Another object of the present invention is to provide a buoyancy aid which has a universal configuration for easy retention by the legs of a swimmer irrespective of the particular size and shape of the legs of the swimmer.
A further object of the invention is to provide a buoyancy aid which can be successfully employed by swimmers of substantially different sizes and weights, i.e., from children to adults with the least needed effort.
A further object of the present invention is to provide a buoyancy aid having varied buoyancy in order to help swimmers of substantially different sizes and weights according to the actually need of the swimmers, and the desired buoyancy of the buoyancy aid is almost fixed or unchanged in water after the buoyancy of the buoyancy aid is decided because the content of the buoyancy aid is flowable or movable inside the buoyancy aid to slightly adjust buoyancy of the buoyancy aid.
In order to achieve the objects set forth, a buoyancy aid includes an integrally formed a body having an inner space formed therein. The body has a spherical portion and a stopper portion, and a connection portion formed therebetween to join them together and being shaped according to a prolate having a outer surface being continue and smooth. The inner space is formed inside of the body and a hole is formed at one end of the spherical portion to communicate the inner space with the outer circumstance.
Especially, a plug installed on the hole is selectively pulled out to allow water or air from the outer circumstance to-enter the inner space so as to adjust buoyancy of the buoyancy aid. And the poured water in the buoyancy aid is able to move toward the buoyancy aid under water to stabilize or balance buoyancy of the buoyancy aid in water and a swimmer can easily control or use it. Besides, two layers of specially treated material is mounted respectively on two opposing lateral faces of the connection portion to provide a soft and easily holding surface thereon for legs of a swimmer so as to facilitate the use of the buoyancy aid during swimming.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.